CN218403826U - Device for reducing formic acid in formaldehyde recovery system - Google Patents
Device for reducing formic acid in formaldehyde recovery system Download PDFInfo
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- CN218403826U CN218403826U CN202220967986.XU CN202220967986U CN218403826U CN 218403826 U CN218403826 U CN 218403826U CN 202220967986 U CN202220967986 U CN 202220967986U CN 218403826 U CN218403826 U CN 218403826U
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Abstract
The utility model discloses a reduce device of formic acid among formaldehyde recovery system: one path of an alkali liquor pipeline is connected with a tower kettle of the formaldehyde recovery tower, the other path of the alkali liquor pipeline is connected with an inlet of a wastewater storage tank, a discharge pipeline of the wastewater storage tank is connected with an inlet of an online static mixer, a discharge port of the online static mixer is connected with a feed inlet of a feed tank of the formaldehyde recovery tower, and a discharge port of the feed tank of the formaldehyde recovery tower is connected with a tube pass inlet of a preheater; a feed inlet at the upper part of the formaldehyde recovery tower is connected with a tube pass outlet of a preheater, a discharge outlet at the top part is sequentially connected with a tower top cooler, a reflux tank and a reflux pump, and a discharge outlet of the reflux pump is respectively connected with a circulating inlet at the upper part of the formaldehyde recovery tower and a crude aldehyde storage tank; connect formaldehyde recovery tower reboiler between formaldehyde recovery tower lower part discharge gate and the circulation import, preheater shell side entry is connected to the lower part discharge gate, and preheater shell side exit linkage is to the wastewater disposal basin. The utility model discloses can effectively reduce the formic acid content among the formaldehyde recovery system, reduce equipment and pipeline corrosion, increase of service life improves and retrieves the formaldehyde quality.
Description
Technical Field
The utility model relates to a reduce the device of formic acid, more specifically say, relate to a reduce the device of formic acid among formaldehyde recovery system.
Background
A formaldehyde recovery system in the polyformaldehyde production device is mainly used for recovering formaldehyde in formaldehyde-containing wastewater of each working section, and a recovered formaldehyde solution with the concentration of about 35% is stored in a crude formaldehyde storage tank and then enters a trioxymethylene and dioxygen pentacyclic process for reaction. The content of formic acid in the wastewater containing formaldehyde is higher, about 2 percent, due to side reaction, formaldehyde oxidation and the like. The operating temperatures of the bottom and the top of the formaldehyde recovery tower are 162.5 ℃ and 147-153 ℃ respectively, the boiling point of formic acid is 100.6 ℃ and is close to that of water, so that after the formaldehyde-containing wastewater enters the formaldehyde recovery tower, most of the formic acid contained in the wastewater escapes from the top of the tower along with the water and the formaldehyde, a formaldehyde solution with the concentration of about 35% is formed after condensation, the content of the formic acid is about 9000pm, and the other part of the formic acid is discharged to a wastewater tank after heat exchange of a preheater along with tower bottom liquid. The light components escaping from the top of the formaldehyde recovery tower and the overhigh formic acid in the heavy components discharged from the tower bottom not only cause the serious corrosion of equipment and pipelines in the formaldehyde recovery system, shorten the service life, but also reduce the quality of the recovered formaldehyde and cause adverse effects on the subsequent participation in production.
SUMMERY OF THE UTILITY MODEL
The utility model aims at overcoming the not enough among the prior art, providing a reduce device of formic acid among formaldehyde recovery system, can effectively reduce the formic acid content among the formaldehyde recovery system, formic acid content is less than 500ppm in making the light component, reduces equipment and pipeline and corrodes, increase of service life improves and retrieves the formaldehyde quality.
The purpose of the utility model is realized through following technical scheme.
The utility model discloses a device for reducing formic acid in a formaldehyde recovery system, which comprises an alkali liquor pipeline, a waste water storage tank, a delivery pump, an online static mixer, a formaldehyde recovery tower feeding tank, a formaldehyde recovery tower feeding pump, a preheater, a formaldehyde recovery tower, a tower top cooler, a reflux tank, a reflux pump, a formaldehyde recovery tower reboiler and a sampling point;
the alkali liquor pipeline is divided into two branch pipelines, one branch pipeline is connected to the tower kettle of the formaldehyde recovery tower, the other branch pipeline and the wastewater pipeline of the trioxymethylene preparation unit are respectively connected to a feed inlet at the top of a wastewater storage tank, a discharge pipeline of the wastewater storage tank and a wastewater pipeline containing formaldehyde are respectively connected to a feed inlet of an online static mixer through a conveying pump, a discharge outlet of the online static mixer is connected to a feed inlet of a feed tank of the formaldehyde recovery tower through a pipeline, and a feed outlet of the feed tank of the formaldehyde recovery tower is connected to a tube pass inlet of a preheater through a feed pump of the formaldehyde recovery tower through a pipeline; the upper feed port of the formaldehyde recovery tower is connected to a tube pass outlet of a preheater through a pipeline, a top discharge port of the formaldehyde recovery tower is sequentially connected with a tower top cooler, a reflux tank and a reflux pump through pipelines, and a discharge port of the reflux pump is respectively connected to an upper circulating inlet of the formaldehyde recovery tower and a crude aldehyde storage tank through pipelines; a reboiler of the formaldehyde recovery tower is connected between a discharge port at the lower part of the formaldehyde recovery tower and the circulating inlet through a pipeline, the discharge port at the lower part of the formaldehyde recovery tower is connected to a shell pass inlet of the preheater through a pipeline, and a shell pass outlet of the preheater is connected to a wastewater tank through a pipeline; the sampling point is arranged on a pipeline between the outlet of the reflux tank and the inlet of the reflux pump.
And a pH value online monitoring device is installed in the feeding groove of the formaldehyde recovery tower.
And the sampling point adopts a duplex opening valve.
Compared with the prior art, the utility model discloses a beneficial effect that technical scheme brought is:
(1) The utility model discloses in successfully being applied to the formaldehyde recovery system of polyformaldehyde device, solved and contained too high corruption formaldehyde recovery system pipeline of formic acid waste water formic acid and equipment problem, prolonged the life of pipeline and equipment.
(2) The utility model discloses can effectively reduce the formic acid content in retrieving the formaldehyde, improve and retrieve the formaldehyde quality, guarantee to retrieve the formaldehyde and subsequently participate in the stability of utilization again.
(3) The utility model discloses sodium formate that acid-base neutralization generated in the operation process is soluble in water easily, can dissolve completely in containing formaldehyde waste water and heavy ends, can not cause the column plate to block up.
(4) The utility model discloses the input cost is low, the time limit for a project is short, easy operation, easily promotes.
Drawings
FIG. 1 is a schematic diagram of the process flow of the method for reducing formic acid in a formaldehyde recovery system of the present invention.
Reference numerals: 1-alkali liquor pipeline, 2-waste water storage tank, 3-delivery pump, 4-online static mixer, 5-formaldehyde recovery tower feeding tank, 6-formaldehyde recovery tower feeding pump, 7-preheater, 8-formaldehyde recovery tower, 9-tower top cooler, 10-reflux tank, 11-reflux pump, 12-formaldehyde recovery tower reboiler and 13-sampling point.
Detailed Description
The present invention will be further described with reference to the accompanying drawings.
As shown in figure 1, the utility model discloses reduce device of formic acid among formaldehyde recovery system, including alkali liquor pipeline 1, waste water storage tank 2, delivery pump 3, online static mixer 4, formaldehyde recovery tower pan feeding groove 5, formaldehyde recovery tower pan feeding pump 6, pre-heater 7, formaldehyde recovery tower 8, top of the tower cooler 9, reflux tank 10, reflux pump 11, formaldehyde recovery tower reboiler 12, sampling point 13.
The alkali liquor pipeline 1 is divided into two branch pipelines, one branch pipeline is connected to the tower kettle of the formaldehyde recovery tower 8, and the other branch pipeline and the waste water pipeline of the trioxymethylene preparation unit are respectively connected to the feed inlet at the top of the waste water storage tank 2. 2 discharge pipe of waste water storage tank is connected to 4 feed inlets of online static mixer respectively through transfer pump 3 and formaldehyde-containing waste water pipe, 4 discharge gates of online static mixer are connected to 5 feed inlets of formaldehyde recovery tower pan feeding groove through the pipeline, 5 discharge gates of formaldehyde recovery tower pan feeding groove are connected to 7 tube side imports of pre-heater through formaldehyde recovery tower pan feeding pump 6 through the pipeline. Wherein, the feeding groove 5 of the formaldehyde recovery tower is provided with a pH value on-line monitoring device for detecting the pH value in real time and guiding the addition of the dilute alkali liquor.
8 upper portion feed inlets of formaldehyde recovery tower pass through pipe connection to export of 7 tube side of pre-heater, 8 top discharge gates of formaldehyde recovery tower have connected gradually top of the tower cooler 9, reflux drum 10, backwash pump 11 through the pipeline, 11 discharge gates of backwash pump are connected to 8 upper portion circulation imports of formaldehyde recovery tower, crude aldehyde storage tank respectively through the pipeline. There is formaldehyde recovery tower reboiler 12 through the pipe connection between 8 lower part discharge gates of formaldehyde recovery tower and the circulation import, 8 lower part discharge gates of formaldehyde recovery tower are connected to 7 shell side entries of preheater through the pipeline, 7 shell side exports of preheater are connected to the wastewater disposal basin through the pipeline. Sampling point 13 sets up on the pipeline between the export of reflux drum 10 to reflux pump 11 entry, sampling point 13 can adopt the pair to open the valve.
The utility model discloses the theory of operation process of the device of formic acid among the reduction formaldehyde recovery system is as follows:
s1, introducing alkali liquor into a wastewater storage tank 2 through an alkali liquor pipeline 1, and mixing the alkali liquor with wastewater of a trioxymethylene preparation unit to obtain dilute alkali liquor. Wherein the alkali liquor is a sodium hydroxide solution with the mass fraction of 10%.
S2, conveying the dilute alkali liquor in the wastewater storage tank 2 to an online static mixer 4 through a conveying pump 3, mixing the dilute alkali liquor with the wastewater containing formaldehyde, conveying the mixture into a feed tank 5 of a formaldehyde recovery tower, neutralizing formic acid in the wastewater containing formaldehyde by using the dilute alkali liquor, and controlling the pH value to be 6.5-7. Wherein, the formaldehyde-containing wastewater consists of waste liquid discharged from a waste gas washing tower, a waste gas recovery tower, a TOX concentration tower and the like.
And S3, conveying the formaldehyde-containing wastewater subjected to deacidification in the formaldehyde recovery tower feeding groove 5 to a preheater 7 through a formaldehyde recovery tower feeding pump 6, performing heat exchange with tower bottom liquid discharged from the formaldehyde recovery tower 8, preheating, and then feeding into the formaldehyde recovery tower 8 for rectification.
And S4, adding alkali liquor into the tower bottom of the formaldehyde recovery tower 8, and neutralizing formic acid in the tower bottom liquor by using the alkali liquor. The alkali liquor and formic acid are subjected to acid-base neutralization reaction to generate sodium formate, the sodium formate is easily dissolved in about 1.3 parts of water, the water content of the formaldehyde-containing wastewater and the water content of the tower bottom liquid are about 86% and 99% respectively, and the sodium formate generated in the acid removal process can be completely dissolved in the formaldehyde-containing wastewater and the tower bottom liquid.
S5, cooling the top gas of the formaldehyde recovery tower 8 by a tower top cooler 9, then feeding the cooled top gas into a reflux tank 10, sampling from a sampling point 13, and analyzing to be qualified, and then performing reflux ratio of 1.4:1, one part of the formaldehyde enters the top of a formaldehyde recovery tower 8 to be used as reflux liquid, and the other part of the formaldehyde enters a crude aldehyde storage tank. Wherein the qualified standard of sampling analysis at the sampling point 13 is that the formaldehyde content is between 35 and 40 percent, the formic acid content is less than 500ppm, and the addition amount of the alkali liquor at the tower bottom is controlled by the formic acid content separated out at the sampling point 13.
S6, heating one part of the tower bottom liquid of the formaldehyde recovery tower 8 by a formaldehyde recovery tower reboiler 12 and then circularly refluxing, and exchanging heat and cooling the other part of the tower bottom liquid with the formaldehyde-containing wastewater discharged from the feed tank 5 of the formaldehyde recovery tower through a preheater 7 and then feeding the other part of the tower bottom liquid into a wastewater tank.
Although the present invention has been described with reference to the accompanying drawings, the present invention is not limited to the above specific functions and operations, and the above specific embodiments are only illustrative and not restrictive, and those skilled in the art can make many forms without departing from the spirit and scope of the present invention, which is within the protection scope of the present invention.
Claims (3)
1. A device for reducing formic acid in a formaldehyde recovery system is characterized by comprising an alkali liquor pipeline (1), a wastewater storage tank (2), a conveying pump (3), an online static mixer (4), a formaldehyde recovery tower feeding tank (5), a formaldehyde recovery tower feeding pump (6), a preheater (7), a formaldehyde recovery tower (8), a tower top cooler (9), a reflux tank (10), a reflux pump (11), a formaldehyde recovery tower reboiler (12) and a sampling point (13);
the alkali liquor pipeline (1) is divided into two branch pipelines, one branch pipeline is connected to the tower kettle of the formaldehyde recovery tower (8), the other branch pipeline and a wastewater pipeline of a trioxymethylene preparation unit are respectively connected to a feed inlet at the top of the wastewater storage tank (2), a discharge pipeline of the wastewater storage tank (2) is respectively connected to a feed inlet of the online static mixer (4) through the delivery pump (3) and a wastewater pipeline containing formaldehyde, a discharge outlet of the online static mixer (4) is connected to a feed inlet of a feed tank (5) of the formaldehyde recovery tower through a pipeline, and a discharge outlet of the feed tank (5) of the formaldehyde recovery tower is connected to a tube pass inlet of a preheater (7) through a feed pump (6) of the formaldehyde recovery tower through a pipeline; the feed inlet at the upper part of the formaldehyde recovery tower (8) is connected to the tube pass outlet of the preheater (7) through a pipeline, the discharge outlet at the top of the formaldehyde recovery tower (8) is sequentially connected with a tower top cooler (9), a reflux tank (10) and a reflux pump (11) through pipelines, and the discharge outlet of the reflux pump (11) is respectively connected to the circulating inlet at the upper part of the formaldehyde recovery tower (8) and a crude aldehyde storage tank through pipelines; a formaldehyde recovery tower reboiler (12) is connected between a discharge port at the lower part of the formaldehyde recovery tower (8) and the circulating inlet through a pipeline, a discharge port at the lower part of the formaldehyde recovery tower (8) is connected to a shell pass inlet of the preheater (7) through a pipeline, and a shell pass outlet of the preheater (7) is connected to a wastewater tank through a pipeline; and the sampling point (13) is arranged on a pipeline between the outlet of the reflux tank (10) and the inlet of the reflux pump (11).
2. The apparatus for reducing formic acid in formaldehyde recovery system according to claim 1, wherein the inlet tank (5) of formaldehyde recovery tower is equipped with a pH value on-line monitoring device.
3. The apparatus for reducing formic acid in formaldehyde recovery system according to claim 1, wherein the sampling point (13) is a double-opening valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220967986.XU CN218403826U (en) | 2022-04-25 | 2022-04-25 | Device for reducing formic acid in formaldehyde recovery system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220967986.XU CN218403826U (en) | 2022-04-25 | 2022-04-25 | Device for reducing formic acid in formaldehyde recovery system |
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| Publication Number | Publication Date |
|---|---|
| CN218403826U true CN218403826U (en) | 2023-01-31 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202220967986.XU Active CN218403826U (en) | 2022-04-25 | 2022-04-25 | Device for reducing formic acid in formaldehyde recovery system |
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| CN (1) | CN218403826U (en) |
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- 2022-04-25 CN CN202220967986.XU patent/CN218403826U/en active Active
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